Air conditioning system



AIR CONDITIONING SYSTEM Filed Nov. 14, 1938 66 6864 50 sl 580 q 63 'is 149 I, H j rf* B 23 l.

20 z Fig. 2

82 asf Z" 98 plg. l @D o 9 39 ;3-7 vhmmor Allwvfim BoNeWfikom BB M Patente'd Dec. 2, 1941 Am coNp'roNiNG SYSTEM Alwin B. Newton, Mlmeapolis, Mimi., assignmto Minneapolis-Honeywell Beglator Company, Minneapolis, Minn., a corporation of Delaware Application November 14, 1938, Serial No. 240,324

6 Claims.

This invention relates to an air conditioning system and more particularly to a system for cooling and dehumidifying the air in a space having heat generating means such as incandescent lights located therein.

In many structures being conditioned,such as oflice buildings, stores, factories, and the like an additional cooling load is placed on the system by reason of the fact that these structures may be provided with a large number of electric lights that are normally kept burning during the occupancy of the building. These lights impose an additional load on the cooling system and in the case of factories, etc., a further load on the cooling system isiimposed by reason ofy the fact` that there may be other heat generating apparatus located therein. In accordance with my invention, it is proposed to reduce the cooling load on the system by conveying the heat generated by the lights or other heat generating apparatus away from the space being heated except when the air conditioning apparatus is being operated solely to effect a reduction in the humidity of the space when the temperature of the space is not excessive. A common method of reducing the humidity is to circulate air over cooling apparatus which reduces the temperature of the air below the dew-point thereof and then reheating the air and conveying it back to the space. If the temperature is at a desirable value, theI heat generated by the various equipment in the space may be effectively utilized to reheat the air which has been cooled to reduce the humidity thereof.

It is therefore an object of my invention to provide means for normally conveying from the space being conditioned the heat generated by the lights and other equipment in the space except at such times as the air conditioning apparatus is being operated solely in order to reduce the humidity thereof, during which time the heat conducting means will be placed out of operation so that the heat generated by the equipment in the space may be'utilized to reheat the air which has been dehumidified.

Other objects and advantages will become apparent upon a study of the specification, claims and appended drawing wherein Figure 1 illustrates diagrammatically one form of a system embodying the principles of my invention, and wherein Figure 2 shows a modification.

Referring more particularly Vto Figure 1, a space to be conditioned is represented by the reference character l0. A fan Il driven by a motor l2 is provided for drawing air from the space I through the conditioning chamber I3 over the conditioning means li which may take the form of an evaporator of a refrigeration system, the cooled and dehumidified air being discharged through the duct l5 and outlet lt back to the space l0.

The refrigeration system may include besides the evaporator M a compressor IB driven by a 5 motor l8, the outlet of the compressor communicating by means of the pipe 20 with the condenser and receiver Zl from which the refrigerant fiows through the pipe 22 into the evaporator M under the control of the expansion valve 23. This expansion valve 23 may be of any suitable construction and may be a thermostatic expansion' valve of the type illustrated in my copending application Serial No. 192,818,

filed February 26, 1938. A pipe 25 connects the outlet of the evaporator lt with the inlet of the compressor 20.

Located within the space I0, light fixtures 28 and 29 are illustrated. These fixtures are shown as comprising bulbs 30 located within the globes 3I, the interior of these globes communicating by means of the ducts 32 with the chamber 33. This chamber 33 has an inlet 34 which may communicate with the outdoor air, there being a suitable lter 35 located adjacent the inlet/'M to remove dirt and other foreign matter from the air entering the chamber 33. Located adjacent the outlet of the chamber 33 is a fan 38 having its inlet connected to a pipe 39 having inlets 40 and dl located within the light fixtures.

The fan 38 may discharge into the outdoor air.

It will be understood-that as the fan 38 is operated, outdoor air will be drawn into the chamber 33 through the inlet 34 and the interior of the light fixtures 28 and 29, then through the pipe 39 to the fan 38 where the air is exhausted into the outdoors. This circulation of air through the light fixtures will effectively remove substantially all of the heat generated by the bulbs 30 while the fan 38 is in operation so that the heat generated by these bulbs will not be dissipated within the space being conditioned.

Located within the space l0 is a thermostat generally indicated by the reference character d5 `and comprising a bellows 46 which may be lled with a suitable volatile fluid and against the upper end of which is biased by means of the spring tl a lever 48 pivoted at ItS. Lever B carries a mercury switch 50 provided with terminals 5l, 52, 53, and 54. As the temperature in the space 50 35 falls, the bellows 08 will contract and the lever 48 will be moved downwardly under the infiuence of the biasing spring tl, and when the temperature has fallen to a low enougli value the switch 50 will be tilted from the position illustrated in which terminals 53 and 56 are connected together by the mercury element to the opposite position in which terminals 5l and 52 will be connected together. Also located within the space l0 is a humidity responsive device element or elements 6I, these elements being fixed at one end at 62 and having their other end connected to a lever 63 pivoted at 64 and biased in a clockwise direction by means of a spring 65. Carried by the lever 63 is a mercury switch 66, this switch including terminals 61 and 68. As the humidity in the space falls, the hygroscopic element 6| will contract whereupon the lever 63 will be moved in a counter-clockwise direction against the action of the biasing spring 65, and when the humidity 'has dropped sufficiently the mercury switch 66 will be tilted to a position wherein the circuit through the contacts 61 and 68 is interrupted. As will be hereinafter set forth, the thermostat 45 and the humidity responsive device 60 each control the operation of the compressor motor l9 and initiate operation thereof whenever the temperature or humidity in the space becomes excessive.

For controlling the operation of the fan 38, a relay generally designated by the reference character 10 is provided. This relay includes a coil 1l and an armature 12 to which is connected switch arm 13 cooperating with a fixed contact 14. When the relay 10 is deenergized, the arm 13 is held in engagement with the contact 14 under the infiuence of gravity or any suitable biasing means, not illustrated. Upon'energization of the relay coil 1l, the armature 12 moves toward the left and carries the arm 13 out of engagement with the contact 14. Line wires 16' With the parts in the positions illustrated, the temperature andhumidity in the space are both excessive. Under these conditions, the compressor motor l9 will be energized by means of 'the following circuit: from the line wire 16, through conductor 18, contacts 54 and 53 of the switch 50, conductors 80, 8l, motor l9, and conductor 82 to the line wire 11. Operation of the motor l9 causes the compressor l8 to circulate refrigerant through the evaporator |4 whereupon the air being drawn thereover by the fan ll will have its temperature reduced to effect a reduction of temperature in the space 10. If the humidity of this air is excessive, the temperature may be reduced below the dew-point thereof, in this manner eiiecting a reduction in the humidity of the air in the space l in a manner well known in the art. Since the temperature in the space is excessive at this time, it is desirable that the fan 38 operate to ventilate the light fixtures 28 and 29. The relay 10 will be deenergized since the circuit therethrough is broken at the terminal of the mercury switch 50 and the arm 13 thereof will be in engagement with the contact 14. Current will now flow through the motor of the fan 38 from the line wire 11 through conductor 85, switch arm 13, contact 14, conductor 86, fan motor 38, and conductor 81 to the line wire 16. Accordingly, the heat generated by the light fixtures 28 and 29 will be removed from the space l0 so that these fixtures will not impose an additional cooling load on the cooling system.

Assume now that the temperature in the space drops to the desired value, whereuponthe mercury switch 50 is tilted in the opposite direction from that illustrated but that the humidity in the space is still excessive. Power will still be supplied to the compressor motor I9 as follows:

from the line wire 1 6, through conductor 90, terminals 61 and 68 of switch 68, conductors 9l, 8I, motor l9, and conductor 82 to the line wire 11. The refrigeration system will acccrdingly be operated so as to reduce the temperature of the air flowing over the evaporator l4 below the dew-point and thus efiect the removal of moisture therefrom. At this time the relay coil 1I will be energized as follows: from the line Wire 16 through conductor 90, mercury switch 66, conductors 9l, 80, contacts 52 and 5| of switch 50, conductor 94, relay coil 1l, and conductor 95 back to the line wire 11. The energization of the relay coil 1l will cause movement of arm 13 away from contact 14 whereupon the circuit to the fan motor 38 is interrupted and air will no longer be drawn through the fixtures 28 and 29 so that the heat generated by these fixtures will be dissipated in the space l0. -It should be noted that the air which has been dehumidified may be introduced into the space |0 in such a manner that it will pass over the light fixtures 28 and 29 so that this air will be reheated by the lights as it is introduced into the space. In this manner, the humidity of the air is reduced by lowering its temperature below the dew-point and then the heat dissipated by the fixtures 28 and 29 is utilized to again reheat the air. ItA will be apparent that if these lights should reheat the air above the desired value, the switch operated by the bellows .46 will be tilted back to the position illustrated, thus interrupting the circuit through the relay 10 and causing the fan 38 to again operate to ventilate the fixtures 28 and 29.

If both the humidity and the temperature in the space have been reduced to their desired values, the Switches 50 and 66 will be tilted in the opposite direction from that illustrated whereupon the compressor motor l9 is deenergized and the relay 'll is likewise deenergized so that the fan 38 operates to ventilate the fixtures 28 and 29 so that the air in the space will not be heated thereby. It will thus be seen that the refrigeration system is placed in operation whenever the temperature or the humidity in the space becomes excessive. It will also be apparent that the fan 38 is operated at all times except when the humidity is excessive and the I temperature is not excessive in which case the refrigeration system will operate only to effect a reduction in the humidity in the space and the heat generated by the fixtures will then be available for reheating the air.l

Referring now to Figure 2, this figure shows a modification wherein the fan 38' corresponding to the fan 38 of Figure 1 is allowed to run constantly, the control of the generated heat being obtained by means of a damper which is controlled by the relay 10'. In this figure the discharge of the fan 38' is connected by a duct leading to outside and by a duct 96 leading to the conditioned space. A damper 91 when in the full line position causes the air to be discharged to atmosphere and when in the dotted line position causes the air to be discharged into the space. This damper 91 may be positioned by a type electric damper motor of a type well known in the art. This type of motor includes a three wire control circuit which is controlled by the switch arm 13' and contacts 14a and 14b of the relay 10'. When this relay is deenergized, the switch arm 13' engages contact 14a which causes the motor 96 to position the damper 91 in the position shown for thereby causing the hot air from the lights to be discharged to atmosphere. When the relay is energized due to the space temperature being low, the switch arm 13' engagesfcontact 'Mb which causes the motor 96 to position damper 97 as shown in dotted lines which causes the air from the lights to be discharged into the space. It will also be understood that any suitable form of air conditioning equipment lmay be utilized for efiecting a reduction in temperature and humidity in the space but my system is particularly applicable wherea reduction in the hu-- midity of the air is effected by passing the airV over a cooling medium. If desired, manual switch means99 may be interposed in the circuit to the fan 38 to interrupt operation thereof when de-- Having described a preferred form 'of my invention, many modifications may become apparent to those skilled in the art and it should therefore be understood that my invention is limited only by the scope of the appended claims.

I claim as my invention:

1. An air conditioning system for a space having heat generating means thlerein, means for preventing heat generated by said generating means from being transferred to the space comprising means for conveying the heat generated by said heat generating means to the outside of the space being conditioned, means for circulating air through the space being conditioned, vcooling means for cooling the air being circulated through the space, temperature and moisture responsive means for causing operation of the cooling means whenever there is a need for the rcmoval of sensible or latent heat from the space, and means for interrupting operation of said heat conveying means in response to a demand for operation of said cooling means for the removal of latent heat only. i

2. An air conditioning system for a space having heat generating means therein, means for preventing heat' generated vby said generating means from being transferredto the space comprising means for conveying the heat generated by said heat generating means to the outside of the space being conditioned, means for circulating air through the. space being conditioned, cooling means for cooling the air being circulated through the space, humidity responsive means for causing operation of the cooling means when the humidity in the space attains an undesirable value, temperature responsive means for causing operation of the cooling means `When the' temperature in the space attains an undesirable value, and means for interrupting operation of said heat conveying means when the cooling means is placed in operation solely by the humidity responsive means.

3. An air conditioning system for a space having heat generating means therein, means for preventing heat generated by said generating means from being transferred to said space comprising means for conveying heat generated by said heat generating means to the outside of the space being conditioned, means for coolirfg"and dehumidifying the air in said space, means for operating said cooling and dehumidifying means in response to the attainment of a high temperarin ture or high relative humidity in the space, and means for interrupting operation of said heat conveying means whenever the cooling means is operated solely in response to a high humidity in the space.

4. An air conditioning system for a space having heat generating means therein, means including fan means and duct means for passing air into heat exchange relationship with said heat generating meansvand for conveying the air heated thereby out of contact with the air in said space to a point outside of said space, whereby the temperature of the space will not be raised appreciably by said heat generating means during the operation of said fan means, means for cooling and dehumidifying the air in said space, temperature responsive means and humidity responsive means in control of said cooling-and dehumidifying means for placing said last mentioned means in operation when the temperature or the humidity of the space attains an undesirable value, means normally causing operation of said fan means, and means controlled by the humidity and temperature responsive means for interrupting operation of said fan means only when the humidity in the space is excessive and the temperature of the space is at or below the desirable value. v

5. An air conditioning system for a space having heat generating means therein, means including fan means and duct means for passing air into heat exchange relationship'with said heat generating means and for conveying the air heated thereby out of contact with the air in said space to a point outside of said space, whereby the temperature of the space will not be raised appreciably by said heat generating means during the operation of said fan means, means for cooling and dehumidifying the air in said space, temperature responsive means and humidity re- -sponsive means in control of said cooling and dehumidifying means for placing said last men-- 'tioned means in operation when the temperaing normally energized lighting means which introduce heat into the space, means for normally ventilating said lighting means in a manner to operation of the ventilating means only when the humidity in the space is excessive and the temiperature is at or below lthe desired value.

ALWIN B. NEWTON. 

